Project description:We use comprehensive and unsupervised transcriptome analyses to provide molecular classifications of sensory neurons in the mouse geniculate ganglion. 96 neurons were isolated on a C1 Fluodigm chip, underwent RNA-Seq, and iteratively clustered into sub-classes.
Project description:The hypothalamic suprachiasmatic (SCN) clock contains several neurochemically defined cell groups that contribute to the genesis of circadian rhythms. Using cell specific and genetically-targeted approaches we have confirmed an indispensable role for vasoactive intestinal polypeptide expressing SCN (SCNVIP) neurons in generating the mammalian locomotor activity (LMA) circadian rhythm. Optogenetic-assisted circuit mapping revealed functional, di-synaptic connectivity between SCNVIP neurons and dorsomedial hypothalamic neurons, providing a circuit substrate by which SCNVIP neurons may regulate LMA rhythms. In vivo photometry revealed that while SCNVIP neurons are acutely responsive to light, their activity is otherwise behavioral state invariant. Single-nuclei RNA-sequencing revealed SCNVIP neurons comprise two transcriptionally distinct subtypes, including putative pacemaker and non-pacemaker populations. Given that SCNVIP neurons constitute ~10% of the total SCN population, and that other cell groups were unable to sustain coherent circadian LMA rhythms following SCNVIP disruption, our findings demonstrate a disproportionately large influence of the SCNVIP cell population on pacemaker function.
